As has already been mentioned, the cathedral crowns the hill, upon the slopes of which the city descends to the river; moreover, the edifice occupies the summit only,--a _castro_, as explained in a previous chapter. Therefore, for proofs are lacking both ways, it is probable that the present building was erected on the same spot where the many basilicas which we know existed and were destroyed in one or another of the many sieges, stood in bygone days.
The present cathedral dedicated to the Virgin Mary, like that in Orense, was most likely begun in the first half of the twelfth century; successive earthquakes suffered by the city, especially that felt in Lisbon in 1755, obliged the edifice to be repaired more than once, which accounts for many of the base additions which spoil the ensemble.
From the general disposition of the building, which is similar in many details to the cathedral at Lugo, it has been thought probable that Maestro Raimundo (father?) was the builder of the church; definite proofs are, however, lacking.
The ground-plan is rectangular, with a square apse; the interior is Roman cruciform, consisting of a nave and two aisles; the transept, like that of Santiago, is also composed of a nave and two aisles; the four arms of the cross are all of them very short, and almost all are of the same length. Were it not for the height of the nave, crowned by a Romanesque triforium of blinded arches, the interior would be decidedly ugly. However, the height attained gives a noble aspect to the whole, and what is more, renders the ensemble curious rather than beautiful.
The large and ungainly choir spoils the general view of the nave, whereas the continuation of the aisles, broad and light to the very apse, where, facing each aisle, there is a handsome rose window which throws a flood of coloured light into the building, cannot be too highly praised.
The walls are devoid of all decoration, and if it were not for the chapels, some of which in default of pure workmanship are richly ornamented, this see of Tuy would have to pass as a very poor one indeed.
The roof of the building has been added lately, doubtless after one of the many earthquakes. It is of a simple execution, neither good nor bad, composed of a series of slightly rounded arches with pronounced ribs.